Does an Air Filter Need a Cover? Everything You Need to Know

Air filter cover for a motorcycle air filter

Air filter covers are protective covers for air filters mainly to prevent water or rain from entering the air filter.

How necessary are they to the air filters is something debatable.

So, does an air filter need a cover?

If the air filter is enclosed and not exposed to the outside atmosphere – there is no need for an air filter cover. If, on the other hand, the air filter is exposed to the outside environment, then an air filter cover is worth it.

That’s the short answer.

Before discussing the details, let’s first understand what are air filter covers and what they do.

What are air filter covers?

An air filter cover encloses the filter to provide an additional layer.

This air cover helps in two ways.

First, the cover protects the air filter from rain and water.

Second, the cover also acts as an additional protection layer from dirt and dust.

2 Air filters with rain sock covers

The primary reason though is still to protect from rain and water.

The air filter itself is designed to filter dust, dirt, and other air contaminants.

So, it does not need an air filter cover to do that.

Of course, an additional layer makes the job easy for the air filter. Also, make it last longer with a better lifespan.

But the primary use of an air filter cover remains to be protection from water.

That’s why an air filter cover is also dubbed asrain sock cover.

Rain sock on a motorcycle air filter

As for why an air filter needs to be protected from water, it’s not good if the air filter gets wet.

A wet air filter will form a dirt layer around the filtering material and will eventually block or restrict the air entry into the engine.

The wet filter mixed with dirt forms a dirt layer. Over time, this dirt layer will slowly clog the air filter.

And once the air filter is clogged, the effects on the motorcycle will be negative.

The motorcycle will have reduced fuel efficiency, decreased engine power and performance, and even power lags. For more details, here is a post on the effects of a clogged air filter.

Does an air filter need a cover?

Now, we know the uses of an air filter cover. But, the question still remains does an air filter need a cover?

First, an air filter cover is not a necessary component required for the air filter.

It is absolutely okay to not have an air filter cover on your motorcycle air filter. Or even your car’s air filter.

Air filter of a motorcycle

Second, most air filters are placed inside a casing.

Either under the motorcycle seat or beside the engine covered with sideways casing. Air filters are not kept open to the outside environment.

Motorcycle Air Filter - cone shaped air filter

When the air filter is not exposed to the outside atmosphere, the chances of getting wet are reduced already.

Rain is the main reason for the motorcycle to get wet and hence the air filter as well.

But if the air filter is not exposed to the outside atmosphere, even heavy rain has little chance of making the air filter get wet.

As a result, the need for an air filter cover becomes unnecessary.

However, if the air filter is indeed exposed to the outside atmosphere, then an air cover can come in handy.

Now, the possibility of the air filter getting wet is far higher.

Even a slight drizzle can make the air filter soaking wet and clog up fast. Having an air filter cover will improve the air filter condition vastly in such cases.

So, having an air cover is useful when the air filter is exposed to the outside atmosphere.

To sum up:

If the air filter is enclosed and not exposed to the outside atmosphere – there is no need for an air filter cover.

If, on the other hand, the air filter is exposed to the outside environment, an air filter cover is indeed useful to have.

Functions of an air filter cover

Here are the functions and the advantages the air filter cover provides:

  • Protects from rain: the air filter cover comes in handy when the air filter is exposed and is vulnerable to rain and water. The cover blocks the rain from entering the filter effectively.
  • Prevents oil stains: the air filter material is susceptible to oil stains and can get clogged easily. The air filter cover prevents such staining and clogging of the filter material.
  • Prevents inhalation of dust: the air filter cover filters out most of the dust present in the air, leaving only the fine dust particles for the air filter.
  • Keeps intake air free from debris, bugs, and large particles: any large particles and debris in the air that might get stuck on the filter material is filtered out.

Pros and Cons

Here are the pros and cons:


  • Increases the air filter life span
  • The air filter won’t get soaked in rain
  • Prevents clogging and dirt layer formation


  • No need for the cover if the air filter is enclosed in a casing
  • Except during heavy rains, the cover has only marginal benefits

Driving without an air filter cover

Driving your motorcycle or car without an air filter cover won’t make much of a difference. Provided the air filter is not soaking wet or clogged up.

As helpful as an air filter cover can be, it is still a tiny component to make that big a difference.

You will not notice much difference while driving with an air filter cover vis-a-vis without an air filter cover.

As a result, if you are driving your motorcycle without an air filter cover, it should be totally fine. There won’t be any problems at all.

The only scenario where it can be a problem is you have your air filter exposed and there is heavy rain while you are driving. In that case, there is no air filter cover to protect the filter from getting soaking wet.

But, even then it is not an emergency. You should be fine.

In short, driving without an air filter is okay. No problems to be faced at all.

Do air filter covers restrict airflow?

An air filter cover does not restrict airflow. Not at all.

Air filter cover

In fact, the air filter cover helps in filtering the dirt and dust and makes the air filter job even easier.

Of course, the cover will not filter finer dust and dirt particles since those are too fine and only the air filter material can filter them out.

Still, large dirt and dust contaminants are easily filtered by the air filter cover itself.

But this in no way restricts the airflow.

Instead, the air filter cover actually enhances airflow into the engine by helping to filter out unnecessary contaminants.

So, in short, air filter covers will NOT restrict the airflow.

Rather, it helps with an improved airflow movement into the filter and then into the engine by filtering out large dirt particles.

Are air filter covers worth it?

Air filter covers have their advantages. If your motorcycle has an air filter exposed to the outer atmosphere, then air filter covers are definitely worth it.

On the other hand, if the air filter is enclosed and is not exposed to the environment directly, air filter covers are not such a necessary accessory.

It still can be useful of course.

Helping whenever you are washing the motorcycle. The cover will prevent water particles from entering the air filter material.

Largely, they are not that necessary unless the air filter is exposed.